Using Embedded SQL

The Structured Query Language, SQL is the de facto standard to manipulate and define data in most relational database systems. It was originally defined by IBM research in 1974, since then numerous database vendors have implemented it.

SQL is a set oriented language based on relational algebra. Every SQL statement uses one or more sets and produces one or more result sets. The set oriented approach is quite different from the traditional record-oriented programming approach. In SQL, you define what you want rather than how you want it done.

The Embedded SQL implementation in DataFlex allows you to issue SQL statements from within a DataFlex program. The SQL statements can be specified by sending messages to SQL broker objects.

Embedded SQL is supported by the following DataFlex SQL Drivers:

The Embedded SQL interface for all three environments is the same. This enables an easy switch from one environment to another. A DataFlex program using Embedded SQL on DB2 can also be used on SQL Server provided the underlying tables are present in both environments and no environment specific syntax has been used. We will indicate server specific issues where appropriate.

This guide starts with a short Introduction to SQL. This introduction is not exhaustive. There are many good books on SQL programming available from beginner to expert level. If you want to know more about SQL, we suggest you to look for such books.

You must also understand the classes that define the SQL broker objects. These are the base SQL handling objects. They handle all SQL activity in a DataFlex program.

See Also

The N Prefix in SQL

Table Character Format in DataFlex

DataFlex SQL Drivers

Understanding How Connectivity Works

Using Managed Connections

Connectivity and Development

Converting Data

Connecting to Existing Data

Connectivity Concepts